Internet Protocol (IP) technology is designed to enable packet-switched interconnection of a heterogeneous set of devices (e.g., computers) and communication networks. A potentially diverse set of network and link layer technologies are interconnected through nodes, e.g., gateways (or routers), that provide a packet forwarding service. Information is transferred between “end nodes” (or hosts) as blocks of data called datagrams, where source and destination hosts are identified by fixed length addresses. Routing in IP internetworks is connectionless in nature, in that datagrams are forwarded by routers on a hop-by-hop basis using the destination address in the datagram.
Mobile IP (MIP) (Ref: IETF RFC 2002, incorporated herein by reference) enables an IP host, also called a “Mobile Node” (MN) in the context of Mobile IP, to dynamically change its point of attachment to the network, yet remain contactable via a previously given “home address”. To achieve this, a temporary local address or “care of address” is associated with the MN when it visits a foreign network, the visited network. In some cases the care of address is that of a “foreign agent” that assists in this process, while in other cases the care of address may be directly assigned to the MN. The care of address is registered back on the home network in a node referred to as the “home agent”. The home agent intercepts packets destined to the home address of the MN and redirects the packets, by means of encapsulation and tunneling, towards the care of address associated with MN in the visited network. Upon delivery to the care of address, the encapsulation is removed and the original packet destined to the home address is delivered to the MN.
Accordingly, MIP enables a moving Internet host to connect to a Foreign Agent (FA) AR in a visited network, yet still be contactable on its persistent Home Address (HoA) that it uses on its home network and is likely contained in a DNS Domain Name Server system. This is possible because the FA gives the host a temporary local address that is either unique to the host (Co-located Care of Address or CCoA) or is unique to the FA (Care of Address or CoA). In various applications, the FA registers its CoA into the HA for the HoA address of its attached MN. The HA then tunnels packets addressed to the HoA of MN to the Care of Address (CoA) of the FA. The FA forwards packets received from the MN HoA out to the Internet as normal, or reverse tunnels the packets to the Home Agent.
A MIP Local Access (LA) service can be supported in a home domain between the MN and a local home agent (HA) in the local access network, wherein the MN uses a Home Address (HoA) from the local HA as an application address. The MIP client registers the FA CoA received from the AR as a care of address for the HoA into the HA. When the MN changes ARs, then the MN can issue another MIP message to the local HA to update the FA CoA of the MN.
A MIP Remote Access (RA) service can also be supported in a visited domain between the MN and a remote home agent in the home domain of the MN, wherein the MN uses a HoA address from a remote Home Agent (HA) as an application address and an IP address from the AR subnet as an interface address. The MIP client then registers the interface address from the AR as a Co-located Care of Address (CCOA) into the Remote HA for the remote HoA. A remote access hand-off is then required when the MN changes AR because the interface address which is also the CCoA of the MN changes and hence needs to be updated in the remote HA.
A limitation of the above existing model is that it only supports one access type at the time, either remote or local access. According to this present invention, however, a MN may employ both local and remote access at the same time.
In addition, well-known deployed operating systems already have MIP clients deployed that perform remote access using the interface address of the MN, and such clients cannot be assumed to be capable of being modified when a MN also seeks to support local access in a wireless network that by implication must have a MIP client capable of supporting fast hand-offs between ARs.
In addition, there is insufficient MIP signaling defined between the MN and the AR to coordinate both remote and local access hand-offs. Finally, there is no MN internal signaling defined that enables the MN to manage address changes for local and remote access interfaces.
In view of the above discussion, it is apparent that there is a need for supporting enhanced end node mobility, communication session establishment and several other operations related to establishing and maintaining communications sessions in systems which use packets to transmit data.